Prediction of infectious complications by the combination of plasma procalcitonin level and localized infection before allogeneic hematopoietic cell transplantation

C-Reactive Protein Is an Independent Predictor of 30-Day Bacterial Infection Post-Liver Transplantation

The relationship between aseptic systemic inflammation and postoperative bacterial infection is unclear. We investigated the correlation of systemic inflammation biomarkers with 30-day clinically significant bacterial infections (CSI) after liver transplantation (LT). This retrospective study enrolled 940 patients who received LT and were followed for 30 days. The primary end point was 30-day CSI events. The cohort was divided into exploratory (n = 508) and validation (n = 432) sets according to different centers. Area under the receiver operated characteristic (AUROC) and Cox regression models were fitted to study the association between baseline systemic inflammation levels and CSI after LT. A total of 255 bacterial infectious events in 209 recipients occurred. Among systemic inflammation parameters, baseline C-reactive protein (CRP) was independently associated with 30-day CSI in the exploratory group. The combination of CRP and organ failure number showed a good discrimination for 30-day CSI (AUROC = 0.80, 95% CI, 0.76–0.84) and the results were confirmed in an external verification group. Additionally, CRP levels were correlated with bacterial product lipopolysaccharide. In conclusion, our study suggests that pre-transplantation CRP is independent of other prognostic factors for 30-day CSI post-LT, and can be integrated into tools for assessing the risk of bacterial infection post-LT or as a component of prognostic models.

Early Warning of Infection in Patients Undergoing Hematopoietic Stem Cell Transplantation Using Heart Rate Variability and Serum Biomarkers

Early warning of infection is critical to reduce the risk of deterioration and mortality, especially in neutropenic patients following hematopoietic stem cell transplantation (HCT). Given that heart rate variability (HRV) is a sensitive and early marker for infection, and that serum inflammatory biomarkers can have high specificity for infection, we hypothesized their combination may be useful for accurate early warning of infection. In this study, we developed and evaluated a composite predictive model using continuous HRV with daily serum biomarker measurements to provide risk stratification of future deterioration in HCT recipients. A total of 116 ambulatory outpatients about to undergo HCT consented to collection of prospective demographic, clinical (daily vital signs), HRV (continuous electrocardiography [ECG] monitoring, laboratory [daily serum samples frozen at -80 °C]), and infection outcome variables (defined as the time of escalation of antibiotics), all from 24 hours pre-HCT to the onset of infection or 14 days post-HCT. Indications for antibiotic escalation were adjudicated as "true infection" or not by 2 blinded HCT clinicians. A composite time series of 8 HRV metrics was created for each patient, and the probability of deterioration within the next 72 hours was estimated using logistic regression modeling of composite HRV and serum biomarkers using a rule-based naïve Bayes model if the HRV-based probability exceeded a median threshold. Thirty-five patients (30%) withdrew within <24 hours owing to intolerability of ECG monitoring, leaving 81 patients, of whom 48 (59%) had antibiotic escalation adjudicated as true infection. The combined HRV and biomarker (TNF-α, IL-6, and IL-7) predictive model began increasing at ∼48 hours on average before the diagnosis of infection, could distinguish between high risk of impending infection (>90% incidence of subsequent infection within 72 hours), average risk (∼50%), and low risk (<10%), with an area under the receiver operating characteristic curve of 0.87. However, given that prophylactic predictive ECG monitoring and daily serum collection proved challenging for many patients, further refinement in measurement is necessary for further study.

Comparison of procalcitonin and C-reactive protein as early diagnostic marker for the identification of transplant-related adverse events after allogeneic hematopoietic stem cell transplantation in pediatric patients

PURPOSE

To evaluate serum procalcitonin (PCT) and C-reactive protein (CRP) as diagnostic biomarkers of transplant-related adverse events (TRAE) in pediatric patients undergoing hematopoietic stem cell transplantation (HSCT).

METHODS

This study analyzed PCT and CRP levels of 214 pediatric patients with a median age of 8.5 years (0.4-17.8 years) undergoing allogeneic HSCT with respect to major TRAE.

RESULTS

26 patients (12.1%) did not experience TRAE (control group), and 188 (87.9%) experienced median 2 (range 1-4) TRAE. Median CRP and PCT were highly and significantly increased during sepsis/SIRS and bacteremia (17.24 mg/dl | 6.30 ng/ml; p < 0.0001 vs. prior values), graft rejection (14.73 mg/dl | 3.20 ng/ml; p < 0.0001), and liver GvHD (6.88 mg/dl | 2.29 ng/ml; p < 0.01). Strong CRP increases and slight/minimal/no PCT increases occurred during fungemia (8.85 mg/dl | 0.72 ng/ml; p < 0.001), intestinal GvHD (8.73 mg/dl | 1.06 ng/ml; p < 0.0001), VOD (10.84 mg/dl | 0.59 ng/ml; p < 0.01), mucositis (8.84 mg/dl | 0.81 ng/ml; p < 0.0001), and viremia (3.62 mg/dl; p < 0.0001 | 0.43 ng/ml; below normal limit). During skin GvHD, CRP and PCT were slightly increased (2.03 mg/dl | 0.93 ng/ml; p < 0.0001).

CONCLUSIONS

CRP and PCT did not show congruent changes during TRAE. PCT was a clinically relevant marker for the early detection and differentiation of severe mucositis and sepsis/SIRS and bacteremia during the critical neutropenic period after HSCT. PCT helped to discriminate acute intestinal GvHD from adenovirus viremia and liver GvHD from hepatic VOD. Thus, PCT may be a valuable parameter to enable a prompt and appropriate treatment during these complications, improving patient outcomes.

Current use and potential role of procalcitonin in the diagnostic work up and follow up of febrile neutropenia in hematological patients

INTRODUCTION

Febrile neutropenia (FN) represents a life-threatening complication in hematological malignancies. Its etiology is most often due to infections even though FN of other origins, such as tumor-related fever and non-infectious inflammation, should rapidly be ruled out. Initially, C-reactive protein and, more recently, procalcitonin (PCT) have been proposed as useful biomarkers for differential diagnosis. PCT was shown to be a good biomarker of bacterial infections and their clinical outcomes. Definition of standard cut-offs and design of PCT-guided treatment protocols remain however to be defined. Areas covered: In this review, highlights on the current clinical use of PCT and its potential role as a diagnostic tool have been discussed by a panel of physicians from different areas of expertise. We provide current clinical evidence that PCT has been shown to be a reliable biomarker to differentiate fever of bacterial origin from other causes. Moreover, the Authors convened to a round-table to discuss their 'real-life experience' and offer their recommendations by a Delphi survey. Expert commentary: PCT has an important clinical role in FN. Issues such as the validation of a specific decision algorithm that includes PCT to monitor antibiotic choice and treatment duration will be addressed in prospective studies.

Procalcitonin and cytokine profiles in engraftment syndrome in pediatric stem cell transplantation

BACKGROUND

Diagnosis of engraftment syndrome (ES) following allogeneic hematopoietic stem cell transplantation (HSCT) can be a challenge due to the systemic presentation and alternative etiologies. With a goal of establishing biomarkers to more accurately distinguish ES, we prospectively analyzed levels of cytokines during HSCT.

PROCEDURES

We performed a prospective study of children ≤21 years who underwent allogeneic HSCT. Blood samples for interleukin (IL)-6, IL-8, IL-10, IL-1b, IL-12p70, interferon-γ, tumor necrosis factor alpha (TNF-α) and procalcitonin were obtained from each subject prior to conditioning, at day 0, and then biweekly through engraftment and at days 30, 60 and 100. Patients were evaluated for ES, infection and acute graft-versus-host disease. Cytokines were analyzed by values at engraftment, and also compared to pre-conditioning and day 0 values to evaluate for change from baseline.

RESULTS

A total of 30 subjects (median age: 7 years, min.-max.: 1-21 years) were enrolled of whom 5 had ES. Characterization of the cytokine profile revealed differences between day 0 from pre-HSCT, with a trend towards differences in IL-10, IL-12p70, interferon-γ and TNF-α at the time of ES. For IL8 and procalcitonin, there was evidence that the absolute difference (or fold change) between engraftment and pre-conditioning or day 0 differed according to ES. In particular, procalcitonin increased from baseline (15.1 median fold increase in ES+ versus 2.31 median fold increase in ES-, P = 0.0006, median difference: 13.8, 95% confidence interval: 6.33, 65.6).

CONCLUSIONS

Our data provide one of the first prospective studies evaluating cytokines in pediatric allogeneic HSCT and suggest that elevated procalcitonin may serve as a biomarker for ES. Further studies to evaluate this finding are warranted.

Early-onset acute kidney injury is a poor prognostic sign for allogeneic SCT recipients

Acute kidney injury (AKI) following stem-cell transplantation (SCT) contributes to a poor prognosis, yet its impact may vary depending on the timing of AKI onset. A prospective cohort study was performed to understand the significance of the onset timing in 103 allogeneic SCT (allo-SCT) recipients. AKI prior to stem-cell engraftment was defined as early AKI and subsequently occurring AKI as late AKI. Propensity score (PS) for early AKI was calculated using a logistic regression model to reduce confounding effects related to differences in clinical background between the early and late AKI groups. The cumulative incidences of early and late AKI were 22.3% and 54.9%, respectively. Non-relapse mortality (NRM) was 39.1% and 7.0%, and overall survival (OS) was 56.5% and 90.9% in early and late AKI at 100 days after AKI, respectively (P<0.001). The cumulative incidence of chronic kidney disease (CKD) over 2 years after SCT was 41.5% and 19.1% in early and late AKI, respectively (P=0.048). Logistic regression analysis adjusted for the PS showed that early AKI was significantly associated with OS (odds ratio (95% confidence interval); 4.63 (1.15-21.4), P=0.031) but with neither NRM (1.25 (0.28-5.33), P=0.766) nor CKD (1.85 (0.41-8.60), P=0.422). In conclusion, early AKI may portend a poor survival for allo-SCT recipients.

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF) directly from positive blood culture flasks allows rapid identification of bloodstream infections in immunosuppressed hosts

INTRODUCTION

In immunosuppressed hosts, rapid identification of microorganisms of bloodstream infections is crucial to ensuring effective antimicrobial therapy. Conventional culture requires up to 72 h from sample collection to pathogen identification.

METHODS

We used the SepsiTyper Kit and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF; Microflex, Bruker) directly from positive blood culture (BacT/ALERT 3D, FN/FA vials; bioMérieux) in comparison to standard culture methodology (VITEK 2; bioMérieux) for species identification.

RESULTS

A total of 62 consecutive positive blood cultures from immunosuppressed patients (solid organ or hematopoietic transplant recipients, or with febrile neutropenia) were analyzed. Culture yielded gram-negative bacteria (GNB) in 27/62 (43.5%) and gram-positive (GPB) in 35/62 (56.5%) vials. For GNB, the predominant species identified by MALDI-TOF and confirmed by VITEK were Escherichia coli (16/16 correctly identified) and Enterobacter cloacae (4/4), with a sensitivity and specificity of 92.6% and 100%, respectively. For GPB, predominant species were Staphylococcus aureus (3/3), coagulase-negative staphylococci (12/24), and Enterococcus faecium (6/6) with a sensitivity of 100%, 60%, and 100%, respectively. The median time from blood collection to species identification was 27.4 h with MALDI-TOF identification and 46.6 h with conventional methodology.

CONCLUSION

Using MALDI-TOF directly from positive blood cultures allowed a shorter time to identification with high sensitivity and specificity in immunosuppressed patients.